What I do is upload or send photos from my phone gallery to photos on computer then save, when you click on insert image top of thread it will go choose image from computer then upload . I never had success doing URL
We use Imgur. Just have the pictures saved on the computers, set up an account and upload the images. It is best to edit the size of the images on Imgur so they are not huge and then there is a option when viewing the to copy for posting online to forums and such. Post your text here and then click and copy and then past the saved link to the message you are posting. Can't be too difficult since even I can figure it out!